Weft braking and positioning device for shuttleless looms



J. L. LLADO Aug. 30, 1966 WEFT BRAKING AND POSITIONING DEVICE FOR SHUTTLELESS LOOMS 5 Sheets-Sheet 1 Filed May 27, 1964 MIKE/V7019! JOSE 11400 14400 By Aug. 30, 1966 J. L. LLADO 3,

WEFT BRAKING AND POSITIONING DEVICE FOR SHUTTLELESS LOOMS Filed May 27, 1964 :5 Sheets-Sheet 2 FIG: 5 I F/G. 6

Josf 11400 11400 Aug. 30, 1966 .1. L. LLADO 3,269,426

WEFT BRAKING AND POSITIONING DEVICE FOR SHUTTLELESS LOOMS Filed May 27, 1964 5 Sheets-Sheet .5

I 1NVENTO R.. JOSE [.LADO LLADO United States Patent 3,269,426 WEFT BRAKING AND POSITIONING DEVICE FOR SHUTTLELESS LOOMS Jos Llado Llado, Calle Jorge Girona Salgado 12, Barcelona, Spain Filed May 27, 1964, Ser. No. 370,502 Claims priority, application Spain, May 30, 1963, 288,908 1 Claim. (Cl. 139122) This invention is for improvements in or relating to weft braking and positioning devices for shuttleless looms.

A disadvantage of the known shuttleless looms is that in the consecutive picks, when the weft yarn reaches the end of its travel, it is cut to initiate further picks, the weft being guided by the weft gripper. The insertion of these wefts beyond the marginal warp yarns leads to a surplus or fringe which gives the fabric an unsatisfactory appearance.

Many attempts have been made, with varying degrees of success, to remove this edge fringe, but all of them are expensive and complicated and have not provided a completely satisfactory solution of the problem. Most of the solutions are based on using shears at the end of the process and a supplementary mechanism, which leads to difficulties and disadvantages inherent in mechanical operation and makes it essential to apply means for removing the surplus weft or waste material. Another disadvantage of the known systems is that the weft yarn pulled by the weft grippers as far as the end of its travel may, at the time of being cut, be broken by the excessive friction produced by the tensioners previously used, or else the wefts may have different tensions so that the finished fabric is not uniform.

This invention obviates these disadvantages and helps to provide uniform fabrics which are devoid of fringes at the selvedge or marginal warp yarn, with no other means than the actual loom.

According to the invention, there is provided a weft braking and positioning device for shuttleless looms comprising a moving vice whose position and movements can be adjusted, said vice being provided in the path of the weft yarn from the supply bobbin to the entry side of the shed, and being arranged to open so as to allow the weft yarn to be pulled through by the weft gripper as far as the end of the travel thereof, to close and clamp the yarn and then to move so as to move the yarn back until the free end of the yarn is in the exact position required relative to the marginal warp thread. The movement of the vice can be varied to suit the technological characteristics of the weft yarn, so that the movement of the weft yarn as far as the marginal warp yarn is compensated for. The vice closes when the weft gripper releases the yarn before starting its movement again to pick up the weft. At this moment the weft yarn, clamped in the vice and pulled thereby, is moved back until its free end is exactly flush with the marginal warp yarn extending from the opposite side of the warp and connected to the weft supply, whereafter the weft yarn is cut at the place where it joins the fabric. The weft yarn clamped in the vice is available to be picked up by the weft gripper, where-upon the vice opens to initiate a further cycle.

The entire system is disposed on the left feed side of the loom, and there is therefore no need for the cutting elements at the other end which are conventionally used in other types of shutterless looms.

The only cutting element needed is disposed near the vice and, like the latter, is operated by cams so synchronized that, when the weft yarn has been picked up by the weft gripper and pulled through the shed to the end of its travel, the vice moves laterally to stretch the yarn,

conditioning it exactly to compensate for the required movement, and immediately afterwards, and synchronously, the weft yarn is cut to cause the weft gripper to continue repeating this operation so that each of the picks goes only as far as the final selvedge--i.e., marginal warp thread.

Consequently, since the travel of the weft gripper, the movement of the vice and the pressure of the vice jaws can all be adjusted, all the picks go exactly as far as the marginal warp thread which is conditioned, enclosed and does not project from the selvedge by the auxiliary weft picks enclosed by the selvedges, so that fringes are completely obviated. As well as marring the appearance of the fabric, the fringes lare wasteful economically because of the loss of material which they represent.

The invention therefore obviates the need for cutting elements at the end of the travel of the weft gripper and obviates the need for devices for removing surplus weft yarns.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a diagrammatic front elevation of that part of the loom to which the improvements according to the invention have been applied;

*FIGURE 2 is a plan View corresponding to FIGURE 1;

FIGURE 3 is another front elevation of the loom shown in FIGURE 1 but with the system in position for moving and conditioning the weft yarn;

FIGURE 4 is a plan view corresponding to FIGURE 3;

FIGURES 5 and 6 are views in side elevation and front elevation respectively of an embodiment of the vice and FIGURES 7 and 8 represent views similar to FIGS. 5 and 6, showing the vice in closed position.

Referring to FIGURES 1 and 2, a weft yarn 2 runs off a bobbin 1 and passes through a yarn guide 3 and between two jaws 4, '5 of a moving vice. The vice is in the open position in which it allows the Weft yarn 2 to pass freely through a yarn guide 6; the vice can also serve as a weft break detector. The weft yarn 2 runs through a combined gripper and support member 7 near a cutting element 8 from which the weft yarn is picked up by a weft gripping and inserting member 9, so that the weft yarn 2 is thereafter pulled by the weft gripping and inserting member 9 as far as the end of the travel thereof.

F'IGURES 3 and 4 show the weft yarn 2 running off the bobbin 1 through .the yarn guide 3 and the vice jaws 4, 5. The vice is now in the closed position and is shifted laterally to draw and condition by braking and positioning the weft yarn 2 passing through the yarn guide 6; the vice can also serve as a weft break detector, the weft being received in a combined gripper and support member 7. When the weft yarn 2 has been beaten-up by the slay 10, the weft yarn 2 is cut by the cutting element 8 at the fell, so that the same is formed by simultaneous and consecutive picks without fringes.

In the embodiment shown in FIGURES 5 to 8 the vice mechanism comprises a spindle 11 driving a laterally slidable cam 12; rigidly secured to the spindle is an adjustable cam 13 which operates a roller 14. The same moves a lever 15 on a spindle 16 against the force of a helical spring 17, the lever 15 operating a rod 18 which continues, by way of an articulation 19, as a rod 20 around which engages a helical spring 21 to facilitate the oper ation. This extension rod 20 receives a bottom jaw S of the vice, such jaw being adapted to clamp the weft yarn 2 against the top jaw 4. The position of the vice can be gradually adjusted vertically as required by means of the bottom jaw 5 and of the support head 22 which latter accordingly comprises a screw 23 for this adjustment. The screw 23 engages a bearing lever 24 which rocks on a spindle 25 mounted in a casting '36 which is mounted on a rod 37. The bottom end forms part of a slide block 26 receiving an arm 27 with a link 28, in order that by operation of an adjusting screw 29 and by means of the displacement of the slide block 26 and link 28, which can be together, an adjustment of the lateral movement of the vice is produced, compensation being provided by an opposing spring 30. The bottom end of the arm 27 bears against a roller 31 operated by the side cam 12 which by its rotation shifts closed jaws 4', 5' (shown in broken lines in FIG. 6 and in full lines in FIGS. 7 and 8) to pull the weft yarn 2 into the required posit-ion.

A further adjustment can be provided by sliding cam 13 along the spindle 11 after loosening an adjusting screw 32 which looks the system together to form a single member.

Fitted to the stationary jaw 4 is an extra plate -33 carried by a sliding screw 34 controlled by a resilient spring or the like 3-5, for resilient adjustment of the pressure required by the weft yarn.

The details and structural features used to carry the invention into practical effect are independent of the su' ject matter of the invention and, without any departure from the scope thereof, the invention can be modified and have additions or can make use of equivalent means. For instance, instead of the lateral displacement of the lever 24 being produced by a split cam which pulls the bottom moving jaw 5 of the vice, the camcan be of the kind having a ramp which compels this movement to occur by means of an appropriate guide.

What I claim is:

In a shuttleless loom having weft thread supply means, weft cut-ting means, means forming a shed of warp threads, weft gripping and inserting means pulling said weft thread through said shed, and a weft clamping and positioning device disposed between said Weft thread supply means and said shed and acting to locate the weft threads in a desired position With respect to said cutting means and to the marginal warps of said shed, said weft clamping and positioning device comprising a pair of jaws, a rocking lever supporting said pair of jaws for reciprocating movement, one of said jaws being movable against the other jaiw for clamping said weft yarn, lever means actuating said movable jaw, cam means reciprocating said rocking lever, cam means actuating said lever means for said movable jaw, and a common shaft carrying both said cam means for rotation, said cam means being so arranged as to close the jaws when said weft gripping and inserting means releases the weft at the end of its travel and simultaneously to move the closed jaws with the clamped weft thread to position the free end of said weft relative to the marginal warp of the shed.

References Cited by the Examiner UNITED STATES PATENTS 1,923,954 8/193 3. Rossman 13 9-125 2,089,620 8/ 1937 Rossman 139-1261 2,553,351 5/1951 Belotti 138127 2,938,547 5/1960 Dewas 139122 2,990,854 7/1961 Pfarwaller 139-126 FOREIGN PATENTS 378,197 7/ 1923 Germany.

MERVIN STEIN, Primary Examiner.

DONALD W. PARKER, Examiner.

H. S. JAUDON, Assistant Examiner. 

